1. Field of the Invention
The invention relates to a method and to a device for producing a printing stencil. In particular, the present invention is directed to preventing displacement in a stencil to be provided using a liquid spray.
2. Conventional Art and Problem
A method for producing a rotary printing stencil is known in which, for the purpose of transferring a pattern stored in an electronic memory, liquid is sprayed out of a nozzle onto a stencil cylinder and applied to the lateral surface of the latter as it rotates the nozzle is driven in accordance with pattern data belonging to the pattern stored in the electronic memory.
The device used for this purpose contains a bearing device for rotatably bearing the stencil cylinder, an electronic memory for storing the pattern, at least one nozzle for spraying out liquid, in order to transfer the pattern onto the lateral surface of the stencil cylinder, and a control device which reads out the pattern with the stencil cylinder rotating and drives the nozzle in accordance with the pattern data read out.
It has been shown that even relatively small and, in particular, relatively strong deviations of the lateral surface of the stencil cylinder from the ideal circular cylindrical form lead to strong displacements of the pattern image in the circumferential direction of the stencil cylinder. The radial eccentricity of the lateral surface of the stencil cylinder gives rise to patterning errors in the tangential direction, because the time between a liquid drop being sprayed out from the nozzle and the liquid reaching the lateral surface becomes longer when the lateral surface moves away from the nozzle and the pattern image is thereby generated on the stencil cylinder with a delay. A corresponding displacement of the pattern image in the circumferential direction also occurs when the lateral surface of the stencil cylinder approaches the nozzle, and premature generation of the pattern image thereby results.